1. Field of the Invention
The present invention relates to a series of novel silanol fatty esters which provide outstanding lubrication, and hydrophobicity to a variety of substrates. The compounds of the invention are waxy solids which melt under pressure to give a clear liquid lubricating oil. The esterification by which the compounds are prepared is the reaction of a silanol, a hydroxy containing silicone polymer, and a fatty acid or polycarboxylic acids.
2. Arts and Practices
Silicone compounds have been known to be active at the surface of plastic, cellulosic and synthetic fibers as well as paper. They are good nondurable lubricants and are very stable to oxidation, however, their high cost and lack of efficiency at low concentrations as well as low durability have made their acceptance in commercial products quite low. In all instances, commercially available quats are the active ingredient in traditional laundry care markets, with little or no silicone added.
The low efficiency and low durability of polydimethylsiloxane is due to the fact that it is very water insoluble and deposits on the surface to obtain a minimum free energy in the solution. Simply, the silicone oil delivery to the surface by hydrophobic binding, not chemical bonding. At the surface, the polydimethylsiloxane is a very effective fiber lubricant, however, there are two drawbacks, first; the polydimethylsiloxane is not chemically bonded so the effect is very transient and disappears with one washing, and second; since there is no reaction of the siloxane to the surface an equilibrium between fiber absorbed polydimethylsiloxane and polydimethylsiloxane in the dispersion results in very inefficient percentage of silicone deposited. A large amount of the expensive silicone goes down the drain with the waste water.
In many applications, there is a desire for a solid wax which can spread on surfaces. These applications include personal care products like antiperspirants and skin creams. Unfortunately, most silicone derivatives are liquid to very low temperatures. Attempts to overcome this deficiency have been made by reacting stearyl alcohol with a chloro silane to obtain the following product; ##STR1##
The difficulty with the use of this material is that a large excess (50% by weight) of the alcohol needs to be added to get a product which is free of the irritating chlorosilane raw material. When such an excess is used the product behaves functionally more like the stearyl alcohol than like a silicone compound. Additionally, the compound is not polymeric, hence the superior lubrication and hydrophobicity enhancements which can be achieved by dimethylpolysiloxane is not obtainable with these compounds.
Many attempts have been made to overcome these problems and get a truly lubricious silicone wax.
U.S. Pat. No. 3,511,699 to Sterman issued May 12, 1970 teaches that epoxy compounds placed in the silicone backbone by hydrosilation can be cured onto certain fibers to give improved substantivity. The substantivity is based upon the reaction of hydroxyl groups on the cellulosic and the epoxy group in the silicone polymer. The resulting bond is a ether linkage and a new hydroxyl group. While a definite improvement over other compounds the efficiency and durability of the were not good enough to allow for cost effective incorporation of these materials in detergent formulations.